I drive a Skyactiv 2013 Mazda 3 2.0 Liter MT 65,000 miles, and recently bought a 2023 CX-5 NA AT bought new, now at 10,000 miles. Over time I noticed pretty much the same noise with the same characteristics in both vehicles. I get to maybe 45 MPH ish, and I hear a whine that slowly raises in pitch with speed.
Both cars drive perfectly normal. Seems unlikely that it’s an issue since both cars do it. I’ve read a post or two where people took their cars to the dealership and they said it was a normal sound that the alternator makes. Interested to see if anyone else experiences this with their car, or has any thoughts on it.
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Alright. I can’t believe no one’s said this yet.
The timing system uses an electric motor to advance/retard the timing on the intake valves. That’s why it sounds like an electronic noise and not a gear noise. This is also why it seems to increase in pitch as you increase RPMs. When the engine is under load like when you’re accelerating, it’s adjusting timing to avoid knock. That’s how the high compression on the skyactive is achieved.
This is just how they sound. My 2.5 NA sounds exactly like you describe.
This makes a ton of sense, do you know if that’s in every Skyactiv engine or was it introduced in one of the revisions?